Alloy



Aug. 2, 1932.

Per ceh Ifo/7 Per cenf I ron O. W. ELLIS ALLOY Filed Dec. 14. 1925Increase in perce/#age elonyafioh,

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INVENTOR Owen W .///ls.-

ATTORNEY Patented Aug. 2, 1932 UNITED STATES lmvr-EN'I' oFFlcla:

OWEN W. ELLIS, F PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSEELEC- TRIC & MANUFACTURING COMPANY, A CORPORATION- OF PENNSYLVANIAl.ALLOY Application led December 14, 1928. Serial No. 326,029.

My invention relates to alloysand more partlcularly to an aluminum brassin which iron Vand manganese have been substituted for part of the zinc.

An object of my invention is to provide an improved aluminum brasshaving an alpha beta or a beta struct-ure that has greater ductility andstrength than previous alloys of this type.

Another object of my invention is to provide an improved aluminumA brasshaving an alpha beta or a beta structure in which iron, or a mixture ofmanganese and iron, has been substituted for part of the zinc in the l5brass in such proportions that the ductility of the alloy is increasedwithout" causing a decrease in its strength.

A further object of my invention is to provide an improved aluminumbrass having an alpha beta or a beta structure in which manganese, or amixture of manganese and iron, has been substituted for the zinc in suchproportions that the strength of the alloy is increased without causinga decrease in its ductility.

Brass composed of 64 to 54% copper and from 46 to 36% zinc, crystallizesupon coolf ing in the alpha beta structure, while brass containingbetween 46 and 50% zinc and from 54 to 50% copper .crystallizes uponcooling in the beta structure.- I-t is a well known Yfact that thesubstitution of aluminum for part of the zinc in a brass having an alphabeta ora beta structure causesan increase in strength and a decrease inductility. Such a substitution also reduces the amount of the alphaconstituent in a brass having an alpha beta structure and if suiicientquantities are adde the alpha constituent can beentirely eliminated.This also has vthe tendency to reduce the ductility of the alloy becausebrass having an alpha beta structure is usually moreductile than brasshaving a beta structure. It will, therefore, be understood that theincrease in strength that can be produced by the substitution ofaluminum' for part pletely, determined by the ductility required. As ageneral rule, the aluminum content of the brass should not exceed 5%,

In order to further increase the strength of an aluminum brass, it hasheretofore been proposed to substltute man anese and iron for part ofthe zinc, and al oys comprising .a beta structure is not always benecialbecause the addition of these ingredients in different roportions'causeswidely divergent results. or example, when they are added in certainproportions they cause a decrease in both the strength and ductility ofthe alloy. Other pro ortions increase the strength of the alloy utreduce the ductility, or, conversely, increase the ductility but reducethe strength.

I have made the discovery that when certain well dened proportions ofiron and manganese are substituted for a. part of the zinc in analuminum brass substantially free from all but accidental traces of tinand having an alpha beta or a beta structure, an alloy `will be producedthat is improved both in ductility and strength. The proportions of ironand manganese may also be varled so that an increase i'n strength may beproduced without affecting the ductility of the alloy, or an increase inductility may be produced without aliecting the strength.

My invention will be better understood by relerlnce to the accompanyingdrawing' in w 1c Figure 1 is a graph showing the proportionsof iron andmanganese which, when substituted for part of the zinc in an aluminumbrass, increase the ductility Without decreasing the strength, and

Fig. 2 is a graph showing the proportions of the same ingredients which,when substituted for a portion of the zinc in a similar brass, increasethe strength without reducing 'the ductility. of the zlnc in a brass islargely, if not com- Referring to Fig. 1 of the drawing, the ordinatesindicate the percentage of iron and the abscissae the percentage ofmanganese to be substituted in the alloy. The dotted line 1 designatesthe increase in percentage elongation in two inches obtained in analuminum brass having an alpha beta or a beta structure when iron andmanganese have been substituted for a part of the zinc in the brass inthe proportions designated by the heavy line 2. While the substitutionof iron and manganese for part of the zinc in the alloy in theproportions indicated by the line 2 produces an alloy having increasedductility, the tensile strength of the alloy is not decreased.

The graph shows that an increase in ductility, as measured'by percentageelongation in two inches, may be obtained without loss of strength, whenthe proportion of iron in the alloy is varied between about 1.25% and4.8% and the proportion of manganese between Oand 5%.

It will be noted that when about 1.6%

iron and about .7% of manganese are substielongation was 21% in twoinches.

tuted for 2.3% of zinc in an aluminum brass, the ductility of the alloyas measured by percentage elongation in two inches will be approximately11% greater than that of ordinary aluminum brass. For example, analuminum brass composed of 58% copper, 2% aluminum and the balance zinc,was tested. The tensile strength ofthe alloy was 87 ,000# per squareinch and the percentage Iron in the proportion of 1.6% and manganese inthe proportion of 0.7% were then substituted for 2.3% of the zinc andthe resulting alloy, consisting of: 58% copper, 2% aluminum, 1.6% iron,0.7 manganese, balance'zinc, had a. tensile strength of 87 000# persquare inch and a percentage elongation of 32% in two inches. p

Referring to Fig. 2 of the drawing, the ordinates and absclssae indicatethe percentages of iron and manganese, respectively, the heavy line 3the percentages of manganese and iron that may be substituted in analuminum brass for a part ofk the zinc without causing a decrease inductility, and the dotted line 4 the increase in tensile strength thatis effected by this substitution. It will be noted from this graph that/when iron and manganese are subs ituted for zinc in an alumik num brasshaving an alpha betal or a beta structure in a range of proportionsbetween 0 and 2% iron, and between 2 and 7% manganese, an improved alloywillbe produced that has a greater-tensile strength than an ordinaryaluminum brass, and is equally as ductile.

While the proportions of iron and manganese represented by any point onthe heavy line 3 in Fig.'2 of the drawing may be utilized,

itis apparent that good results may be produced by substituting about 1%iron and about 3.65% of manganese for 4.65% of zinc in an aluminum brasshaving an alpha beta or a beta structure, and that the increase intensile strength which is obtained by making a greater substitution isvery limited. When iron and manganese in the proportions just speciedwere substituted for 4.65% zinc in an aluminum brass containing 58%copper, 2% aluminum and the balance zinc, an alloy was produced havingthe following composition: 58% copper, 2% aluminum, 1% iron, 3.65%manganese, balance zinc. This alloy had a tensile strength of 93,700#per square inch while the tenslle strength of the original alloy wasonly 87 ,000#. The ductility of the two alloys, as determined by thepercentage of elongation; was practically the same.

Since the 1 proportions of iron and manganese that are effective incausing an increase in ductility without causing a decrease in strengthrange from 11/2 to 5% iron and from 0 to 5% manganese and theproportions of the same ingredients that cause an increase in strengthwithout causing a loss 1n ductllity range from v0 to 2% iron and 2 to 7%manganese, it will be obvious that when the proportions of iron andmanganese are maintained within the limits of 117/2 to 2% iron and 2 to5% manganese, alloys having both an increased strength and ductilitywill be produced.

It will be recognized that in practice, it is diflicult to produce analloy having the exact percentages represented by the heavy lines 2 and3 in Figs. 1 and 2 and where specific proportions of the ingredients arementioned in the claims, lit is Vcontemplated that there may be somevariations in manufacture, such as an increase or decrease of about .25%of either or botlthe manganese and iron.

W'hi I have described a preferred embodiment of my invention and haveillustrated by examples and graphs the proportions of iron andmanganese, which when substituted for zinc in an aluminum brass havingan alpha beta or a beta structure, produce an alloy having the desiredcharacteristics, it wil be understood that various modiications may bemade therein without departing from the spirit of my invention.

For example, the aluminum content may be varied fromrO to 5% and theiron and manxganese may be varied within those ranges that l willproduce an alloy having increased strength and ductility, an increasedductility without a decrease in strength, or an increase in strengthwithout loss in ductility. It will also be understood that varying.amounts of impurities may be present in the alloys.. It is essentialhowever that the proportion of tin should be kept below a 4range of .5to .75% because of its deleterious properties.

Other modifications of my invention will be apparent to those skilled inthe art. I, therefore, desire that only such limitations shall beimposed thereon as are required by the PIOF mit and the appended claims.

I claim as my invention:

1. An alloy comprising zinc, copper, aluminum, iron and manganese thatis substantially free from tin, the zinc, copper and aluminum beingpresent in such proportions that the alloy Will crystallize in the alphabeta or beta structure, the proportion of iron u being less than 2% andthe proportion of manganese being less than 2.5%.

2. An alloy comprising zinc, copper, aluminum, iron and manganese thatis substantially free from tin, the zinc, copper and aluminum beingpresent in such proportions that the alloy will crystall'ize in thealpha beta or minum being present in such proportions that the alloyWill crystallize in the alpha beta or beta structure, the proportion ofiron being .fat least 1% but less than 2%, and the proportion ofmanganese being less than 2.5%.

4. An alloy comprising zinc, copper, aluminum, iron and manganese, thezinc, copper and aluminum being present in suchproportions that thealloy Will crystallize in the alpha beta or beta structure, the amountof iron being greater than .75% but less thanV 2%, the amount ofaluminum being less than 5% and the amount of manganese ranging from.25% to 2%.

In testimony Whereof,.I have hereunto subscribed my name this 12th dayof December, 1928.

OWEN W. ELLIS.

